Gao X P, Suzuki H, Olopade C O, Pakhlevaniants S, Rubinstein I
Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
J Appl Physiol (1985). 1997 Jul;83(1):74-81. doi: 10.1152/jappl.1997.83.1.74.
The purpose of this study was to determine whether purified angiotensin I-converting enzyme (ACE) attenuates smokeless tobacco extract (STE)-induced increase in macromolecular efflux from the in situ oral mucosa. By using intravital microscopy, we found that suffusion of an aqueous extract of smokeless tobacco elicited significant concentration-dependent leaky site formation and increase in clearance of fluorescein isothiocyanate-labeled dextran (mol mass, 70 kDa) from the hamster cheek pouch (P < 0.05). Suffusion of purified rabbit lung ACE significantly attenuated these responses in a concentration-dependent fashion (P < 0.05). These effects were specific because purified ACE also significantly attenuated the increase in macromolecular efflux elicited by bradykinin, which is produced in the cheek pouch during suffusion of STE, but did not attenuate the increase elicited by adenosine. Moreover, suffusion of heat-inactivated purified ACE and purified superoxide dismutase had no significant effects on STE- and bradykinin-induced responses. Collectively, these data suggest that exogenous ACE attenuates STE-induced increase in macromolecular efflux from the in situ oral mucosa, in part, by promoting local bradykinin catabolism.
本研究的目的是确定纯化的血管紧张素I转换酶（ACE）是否能减弱无烟烟草提取物（STE）诱导的原位口腔黏膜大分子外排增加。通过活体显微镜观察，我们发现灌注无烟烟草水提取物会引起明显的浓度依赖性渗漏部位形成，并增加仓鼠颊囊对异硫氰酸荧光素标记的葡聚糖（分子量70 kDa）的清除率（P < 0.05）。灌注纯化的兔肺ACE能以浓度依赖性方式显著减弱这些反应（P < 0.05）。这些作用具有特异性，因为纯化的ACE还能显著减弱缓激肽引起的大分子外排增加，缓激肽是在灌注STE期间在颊囊中产生的，但不能减弱腺苷引起的增加。此外，灌注热灭活的纯化ACE和纯化的超氧化物歧化酶对STE和缓激肽诱导的反应没有显著影响。总体而言，这些数据表明外源性ACE部分通过促进局部缓激肽分解代谢来减弱STE诱导的原位口腔黏膜大分子外排增加。
